Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/65892387e9bb
Author: Ghislain 'Aus' Lacroix <aus@noiseport.org>
Desc: Merge pull request #16637 from nullaus/bug952695

bug 952695

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https://hg.mozilla.org/integration/gaia-central/rev/1039e1070f75
Author: Ghislain 'Aus' Lacroix <aus@mozilla.com>
Desc: bug 952695

* Clear all completed downloads from mozDownloadManager when Gaia Download Manager inits.
* update mockMozDownloadManager to have getDownloads() and clearAllDone() for unit-test purposes.

r=crdlc
Bumping manifests a=b2g-bump